Yes, you can create as many associations as you want between non-persistable entities. As they are NP, the only difference here is that they won't be stored in the database.
If you are planning to use a large ‘tree’ of objects, you might want to consider using a database approach in order to free more memory during the processing of these objects.
Hey harsh, yes we can have association between two non-persistent entities. We can have all 3 types of association between them.